Solar-control glazing unit

Abstract

The present invention relates to a substrate bearing a solar-control multilayer stack, and to a multiple glazing unit and to a laminated glazing unit incorporating at least one such substrate bearing a solar-control stack. The multilayer stack comprises three functional films, each film, starting from the substrate, being thicker than the preceding one, and four transparent dielectric coatings. The ratio of the optical thickness of the third dielectric coating, to the optical thickness of the final dielectric coating, lies between 2 and 3.2, and the ratio of the optical thickness of the third dielectric coating, to the optical thickness of the second dielectric coating, is either between 0.6 and 0.91 or between 1.15 and 1.7. The invention is applicable, in particular, to production of high-selectivity solar-control glazing units.

The invention claimed is: 
     
       1. A transparent substrate comprising a solar-control multilayer stack comprising three functional films based on a material that reflects infrared and four dielectric coatings, wherein
 each functional film is sandwiched between dielectric coatings, 
 a geometric thickness of the second, counting from the substrate, functional film is larger than a geometric thickness of the first functional film and a geometric thickness of the third functional film is larger than the geometric thickness of the first functional film, 
 a ratio of an optical thickness of the transparent dielectric coating placed between the second and third functional films, to an optical thickness of a final transparent dielectric coating placed on a last functional film, is between 2 and 3.2, and 
 the ratio of the optical thickness of the transparent dielectric coating placed between the second and third functional films, to an optical thickness of the transparent dielectric coating placed between the first and second functional films, is between 1.3 and 1.7. 
 
     
     
       2. The transparent substrate according to  claim 1 , wherein the ratio of the optical thickness of the transparent dielectric coating placed between the second and third functional films, to the optical thickness of the final transparent dielectric coating placed on the last functional film, is between 2.1 and 3. 
     
     
       3. The transparent substrate according to  claim 1 , wherein the second functional film is between 12 and 16 nm in thickness, and an optical thickness of the first dielectric coating deposited on the substrate is between 44 and 86 nm. 
     
     
       4. The transparent substrate according to  claim 1 , wherein the geometric thickness of the first functional film is between 9 and 14 nm. 
     
     
       5. The transparent substrate according to  claim 1 , wherein the geometric thickness of the last, counting from the substrate, functional film is between 11.5 and 17 nm. 
     
     
       6. The transparent substrate according to  claim 1 , wherein the optical thickness of the second transparent dielectric coating, placed between the first and second functional films, is between 138 and 170 nm. 
     
     
       7. The transparent substrate according to  claim 1 , wherein the optical thickness of the third transparent dielectric coating, placed between the second and third functional films, is between 101 and 155 nm. 
     
     
       8. The transparent substrate according to  claim 1 , wherein the optical thickness of the final transparent dielectric coating, placed on the last functional film, is between 40 and 76 nm. 
     
     
       9. The transparent substrate according to  claim 1 , wherein the ratio of an optical thickness of the first transparent dielectric coating, placed between the substrate and the first functional film, to the optical thickness of the final transparent dielectric coating, placed on the last functional film, is between 0.5 and 1.7. 
     
     
       10. The transparent substrate according to  claim 1 , wherein the ratio of the geometric thickness of the third functional film, to the geometric thickness of the second functional film, counting from the substrate, is between 0.9 and 1.35. 
     
     
       11. The transparent substrate according to  claim 1 , wherein the ratio of the optical thickness of the second transparent dielectric coating, placed between the first and second functional films, to the optical thickness of the first transparent dielectric coating, placed between the substrate and the first functional film, is between 1.6 and 3.8. 
     
     
       12. The transparent substrate according to  claim 1 , wherein the ratio of the optical thickness of the transparent dielectric coating placed between the second and third functional films, to the optical thickness of the transparent dielectric coating placed between the first and second functional films, is between 1.3 and 1.5. 
     
     
       13. The transparent substrate according to  claim 12 , wherein the ratio of the optical thickness of the transparent dielectric coating placed between the second and third functional films, to the optical thickness of the final transparent dielectric coating placed on the last functional film, is 2.2 or more. 
     
     
       14. The transparent substrate according to  claim 12 , wherein the geometric thickness of the first, counting from the substrate, functional film is between 8 and 12 nm. 
     
     
       15. The transparent substrate according to  claim 12 , wherein the geometric thickness of the last, counting from the substrate, functional film is between 16 and 20 nm. 
     
     
       16. The transparent substrate according to  claim 12 , wherein the optical thickness of the second transparent dielectric coating, placed between the first and second functional films, is between 105 and 150 nm. 
     
     
       17. The transparent substrate according to  claim 12 , wherein the optical thickness of the third transparent dielectric coating, placed between the second and third functional films, is between 152 and 175 nm. 
     
     
       18. The transparent substrate according to  claim 12 , wherein the optical thickness of the final transparent dielectric coating, placed on the last functional film, is between 58 and 82 nm. 
     
     
       19. The transparent substrate according to  claim 12 , wherein the ratio of the optical thickness of the first transparent dielectric coating, placed between the substrate and the first functional film, to the optical thickness of the final transparent dielectric coating, placed on the last functional film, is between 0.5 and 1.2. 
     
     
       20. The transparent substrate according to  claim 12 , wherein the ratio of the geometric thickness of the third functional film, to the geometric thickness of the second functional film, is between 1.1 and 1.8. 
     
     
       21. The transparent substrate according to  claim 12 , wherein the ratio of the optical thickness of the second transparent dielectric coating, placed between the first and second functional films, to an optical thickness of the first transparent dielectric coating, placed between the substrate and the first functional film, is between 1.5 and 2.6. 
     
     
       22. A multiple glazing unit, comprising a transparent substrate according to  claim 1 . 
     
     
       23. The multiple glazing unit according to  claim 22 , wherein, when the solar-control multilayer stack is deposited on a 6 mm-thick sheet of ordinary clear soda-lime float glass that is itself associated, by way of a gas-filled cavity, with a 4 mm-thick sheet of ordinary clear soda-lime float glass, a light transmission T L  is greater than 51%. 
     
     
       24. The multiple glazing unit according to  claim 22 , wherein a solar factor of the unit is 34% or less. 
     
     
       25. The multiple glazing unit according to  claim 22 , wherein a selectivity of the unit is greater than 1.95. 
     
     
       26. A multiple glazing unit comprising a transparent substrate according to  claim 1 , wherein the unit is assembled with a sheet of vitreous material via an adhesive plastic. 
     
     
       27. A tempered glazing unit comprising an antisolar stack comprising three functional films based on a material that reflects infrared and four dielectric coatings, wherein
 each functional film is sandwiched between dielectric coatings, 
 a geometric thickness of the second, counting from a substrate, functional film is larger than a geometric thickness of the first functional film and a geometric thickness of the third functional film is larger than the geometric thickness of the first functional film, 
 a ratio of an optical thickness of the transparent dielectric coating placed between the second and third functional films, to an optical thickness of a final transparent dielectric coating placed on a last functional film, is between 2 and 3.2, and 
 a ratio of the optical thickness of the transparent dielectric coating placed between the second and third functional films, to the optical thickness of the transparent dielectric coating placed between the first and second functional films, is either between 0.6 and 0.9 or between 1.15 and 1.7, 
 the glazing unit having undergone a tempering heat treatment, a bending heat treatment, or both, at a temperature above 560° C., and 
 wherein the substrate bearing the antisolar stack has a Deltacol (R G ) value of less than 2.1. 
 
     
     
       28. The tempered glazing unit according to  claim 27 , wherein the glazing unit has a selectivity of at least 1.95. 
     
     
       29. A transparent substrate comprising a solar-control multilayer stack comprising three functional films based on a material that reflects infrared and four dielectric coatings, wherein
 each functional film is sandwiched between dielectric coatings, 
 a geometric thickness of the second functional film, counting from a substrate, is larger than a geometric thickness of the first functional film and a geometric thickness of the third functional film is larger than the geometric thickness of the first functional film, 
 a ratio of an optical thickness of the transparent dielectric coating placed between the second and third functional films, to an optical thickness of a final transparent dielectric coating placed on a last functional film, is between 2 and 3.2, and 
 a ratio of the optical thickness of the transparent dielectric coating placed between the second and third functional films, to an optical thickness of the transparent dielectric coating placed between the first and second functional films, is between 0.6 and 0.85. 
 
     
     
       30. The transparent substrate according to  claim 29 , wherein the second functional film is between 12 and 16 nm in thickness, and an optical thickness of the first dielectric coating deposited on the substrate is between 44 and 86 nm. 
     
     
       31. The transparent substrate according to  claim 29 , wherein the ratio of the optical thickness of the transparent dielectric coating placed between the second and third functional films, to the optical thickness of the final transparent dielectric coating placed on the last functional film, is between 2.1 and 3. 
     
     
       32. The transparent substrate according to  claim 29 , wherein the geometric thickness of the first functional film is between 9 and 14 nm. 
     
     
       33. The transparent substrate according to  claim 29 , wherein the geometric thickness of the last, counting from the substrate, functional film is between 11.5 and 17 nm. 
     
     
       34. The transparent substrate according to  claim 29 , wherein the optical thickness of the second transparent dielectric coating, placed between the first and second functional films, is between 138 and 170 nm. 
     
     
       35. The transparent substrate according to  claim 29 , wherein the optical thickness of the third transparent dielectric coating, placed between the second and third functional films, is between 101 and 155 nm. 
     
     
       36. The transparent substrate according to  claim 29 , wherein the optical thickness of the final transparent dielectric coating, placed on the last functional film, is between 40 and 76 nm. 
     
     
       37. The transparent substrate according to  claim 29 , wherein a ratio of an optical thickness of the first transparent dielectric coating, placed between the substrate and the first functional film, to the optical thickness of the final transparent dielectric coating, placed on the last functional film, is between 0.5 and 1.7. 
     
     
       38. The transparent substrate according to  claim 29 , wherein the ratio of the geometric thickness of the third functional film, to the geometric thickness of the second functional film, counting from the substrate, is between 0.9 and 1.35. 
     
     
       39. The transparent substrate according to  claim 29 , wherein the ratio of the optical thickness of the second transparent dielectric coating, placed between the first and second functional films, to the optical thickness of the first transparent dielectric coating, placed between the substrate and the first functional film, is between 1.6 and 3.8. 
     
     
       40. A multiple glazing unit, comprising a transparent substrate according to  claim 29 .